Subject: Re: ARRAY() returning NULL instead of ARRAY[] resp. {}
From: Markus Bertheau <twanger@bluetwanger.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Joe Conway <mail@joeconway.com>, pgsql-sql@postgresql.org
In-Reply-To: <16774.1116907560@sss.pgh.pa.us>
References: <1116873219.7306.0.camel@localhost.localdomain>
	<42923762.7010708@joeconway.com>  <16774.1116907560@sss.pgh.pa.us>
Content-Type: multipart/signed; micalg=pgp-sha1;
	protocol="application/pgp-signature";
	boundary="=-i6yZVA3SXsNrNAvBJqE3"
Date: Tue, 24 May 2005 08:02:25 +0200
Message-Id: <1116914546.7306.0.camel@localhost.localdomain>
Mime-Version: 1.0


--=-i6yZVA3SXsNrNAvBJqE3
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable

Dnia 24-05-2005, wto o godzinie 00:06 -0400, Tom Lane napisa=C5=82(a):
> Joe Conway <mail@joeconway.com> writes:
> > Markus Bertheau wrote:
> >> why does SELECT ARRAY(SELECT 1 WHERE FALSE) return NULL instead of
> >> ARRAY[] resp. '{}'?
>=20
> > Why would you expect an empty array instead of a NULL?
>=20
> I think he's got a good point, actually.  We document the ARRAY-with-
> parens-around-a-SELECT syntax as
>=20
> 	The resulting one-dimensional array will have an element for
> 	each row in the subquery result, with an element type matching
> 	that of the subquery's output column.
>=20
> To me, that implies that a subquery result of no rows generates a
> one-dimensional array of no elements, not a null array.
>=20
> The point Markus is complaining about seems like it should
> be easily fixable.

Great :) Is this a TODO?

--=20
Markus Bertheau <twanger@bluetwanger.de>

--=-i6yZVA3SXsNrNAvBJqE3
Content-Type: application/pgp-signature; name=signature.asc
Content-Description: This is a digitally signed message part

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.5 (GNU/Linux)

iD8DBQBCksNu2RUnMPztcykRAsULAJ9ZRAO32YckhekamYpfqRV+pu6VAgCeIVe5
tf99JAQqKjltbv+A0hpEZE4=
=dhis
-----END PGP SIGNATURE-----

--=-i6yZVA3SXsNrNAvBJqE3--